tests/tcg/s390x/cdsg.c

   1 /*
   2  * Test CDSG instruction.
   3  *
   4  * Increment the first half of aligned_quadword by 1, and the second half by 2
   5  * from 2 threads. Verify that the result is consistent.
   6  *
   7  * SPDX-License-Identifier: GPL-2.0-or-later
   8  */
   9 #include <assert.h>
  10 #include <pthread.h>
  11 #include <stdbool.h>
  12 #include <stdlib.h>
  13
  14 static volatile bool start;
  15 typedef unsigned long aligned_quadword[2] __attribute__((__aligned__(16)));
  16 static aligned_quadword val;
  17 static const int n_iterations = 1000000;
  18
  19 static inline int cdsg(unsigned long *orig0, unsigned long *orig1,
  20                        unsigned long new0, unsigned long new1,
  21                        aligned_quadword *mem)
  22 {
  23     register unsigned long r0 asm("r0");
  24     register unsigned long r1 asm("r1");
  25     register unsigned long r2 asm("r2");
  26     register unsigned long r3 asm("r3");
  27     int cc;
  28
  29     r0 = *orig0;
  30     r1 = *orig1;
  31     r2 = new0;
  32     r3 = new1;
  33     asm("cdsg %[r0],%[r2],%[db2]\n"
  34         "ipm %[cc]"
  35         : [r0] "+r" (r0)
  36         , [r1] "+r" (r1)
  37         , [db2] "+m" (*mem)
  38         , [cc] "=r" (cc)
  39         : [r2] "r" (r2)
  40         , [r3] "r" (r3)
  41         : "cc");
  42     *orig0 = r0;
  43     *orig1 = r1;
  44
  45     return (cc >> 28) & 3;
  46 }
  47
  48 void *cdsg_loop(void *arg)
  49 {
  50     unsigned long orig0, orig1, new0, new1;
  51     int cc;
  52     int i;
  53
  54     while (!start) {
  55     }
  56
  57     orig0 = val[0];
  58     orig1 = val[1];
  59     for (i = 0; i < n_iterations;) {
  60         new0 = orig0 + 1;
  61         new1 = orig1 + 2;
  62
  63         cc = cdsg(&orig0, &orig1, new0, new1, &val);
  64
  65         if (cc == 0) {
  66             orig0 = new0;
  67             orig1 = new1;
  68             i++;
  69         } else {
  70             assert(cc == 1);
  71         }
  72     }
  73
  74     return NULL;
  75 }
  76
  77 int main(void)
  78 {
  79     pthread_t thread;
  80     int ret;
  81
  82     ret = pthread_create(&thread, NULL, cdsg_loop, NULL);
  83     assert(ret == 0);
  84     start = true;
  85     cdsg_loop(NULL);
  86     ret = pthread_join(thread, NULL);
  87     assert(ret == 0);
  88
  89     assert(val[0] == n_iterations * 2);
  90     assert(val[1] == n_iterations * 4);
  91
  92     return EXIT_SUCCESS;
  93 }